Losing weightbelt, nitrogen level

[maaaarius]

Hi! I'm new to diving and have two questions I would like someone out there to answer.

What do I do if I loose my weightbelt? It has actually happend once, but I wasn't very deep so no problems there. Is it ok to hang onto another diver or will that just cause more problems like maybe taking the other diver with me in my run away acsent. I always check my belt twice now, but what if it happens again but this time on 30 meters?

I have question regarding nitrogen level and no-decompression limits. If I take a look at my dive tabel (sorry, but I don't remember the name of this table) and look at 30 meters th table shows that 20 minutes is the maximum allowed bottom time. I guess this is because the nitrogen level in my body is getting very high. Lets say that I go diving with a friend, we both have 10 liter tanks, 200 bar. Ee stay at 30 meters for 20 minutes, my friend has 50 bars left while I have 100. Ok, we have reach the maximum bottom time, but if this maximum bottom time has to do with the amount of nitrogen in our body, won't that mean that I could actually stay at 30 meters a bit longer since I have only used 100 bar, and not 150 like my buddy. If I use less air, doesn't that mean I have less nitrogen in my body as well? With nitrox you breath less nitrogen and can therefor stay down longer (if you have air) as far as I know.

I have absolutely no plans on staying beyond the limits of my table or computer, but I would like to understand how this works.

Answers to these two questions would be highly appreciated.

 

[DA Aquamaster]

To answer your last question first - absolutely not. Having lower air consumption does not mean you have taken up less nitrogen.

It's also never a good idea to push the no decompression limits as decompression theory is just that - theory. Deco tables are basedon models of the effects of nitorgen on divers in general but the responses of indivudual divers on individual days probably varies somewhere around whatever curve is precdicted by the model. So a healthy safety factor is needed to stay out of trouble even when you follow the rules.

Ascent rate is also a critical factor in decompression - I would argue that it is a lot more important consideration than most divers think. If a table is designed for a 30 ft / 10 meter per minute ascent rate, that is exactly what it means and your ascent rate should be no more than that, and less is usually better.

That obviously makes a no weightbelt ascent very problematic and it obviously precludes doing the safety stop more or less mandated by most tables and computers when diving below 60 ft.

Most technical/decompression divers are not big fans of ditchable weight as it poses an unacceptable risk during a decompression dive where making your deco stops is not optional. Thise who use ditchable weightbelts usually put them on under the crotch strap of their BP/wing to provide an additional level of safety if it comes loose.

As for holding onto another diver, if the other diver is properly weighted, he or she probably won't have enough extra negative bouyancy to keep you down as well, particulalry late in the dive when the weight of the gas in a full tank is no longer there. This is particularly true in cold water diving situations where a heavy exposure suit is used.

I hold the view that the only appropriate time to dump weight is for a diver who is on the surface and struggling to maintain positive bouyancy. Personally, I am a fan of nonditchable trim weights as well as weight integration puches as it spreads the weight over 3 or 4 different locations so that loss of one weight pouch is not overly critical and will still usually allow you to stay neutral at about 25-30 feet for a slightly deeper than normal safety stop. My integrated weight pouches are also equipped with fastex buckles that require a two step process to ditch, making unitentional loss of a pouch very unlikely.

I had a dive buddy who managed to lose both weight pouches once while diving at about 90 ft. At depth bouyancy was not really a problem as she was only a couple pounds positive. but had she ascended, the expansion of the suit would have resulted in her ascent read steadily increasing the closer she got to the surface. The solution in this case was to doa quick search for the lost pouches, replace the one we could fine and then compensate for the remaining missing pouch by filling a large fold out pocket with a suitable amount of rocks off the bottom. It was not elegant but it did allow a normal ascent. After that dive she had me modify her pockets to incorporate a fastex buckle to prevent a repeat occurrence.

 

[Ber Rabbit]

Hi! I'm new to diving and have two questions I would like someone out there to answer.

What do I do if I loose my weightbelt? It has actually happend once, but I wasn't very deep so no problems there. Is it ok to hang onto another diver or will that just cause more problems like maybe taking the other diver with me in my run away acsent. I always check my belt twice now, but what if it happens again but this time on 30 meters?

A runaway ascent from shallow depths can be dangerous or deadly if you hold your breath. The biggest change in volume is in the first atmosphere or 33 feet sea water (34 feet fresh water). The volume of air in your lungs will double on an ascent from 33 feet and cause an air embolism if you are holding your breath.

Here's my experience with losing a weightbelt. We were diving as a threesome, I was side-by-side with one buddy and the other was following us and towing the flag. I felt something tugging on my weightbelt and thought I had gotten tied up in the flag rope. I turned to look for the trailing buddy and he was right behind us and the rope was nowhere near me. Next thing I knew the weightbelt came off, I wasn't fast enough to grab it as it slid over my hips. I instinctively reached to my left for my buddy (without looking) and grabbed him while flaring for the ride up from 40 feet. I felt him grab my hand so I looked at him and saw that I had grabbed his regulator hose and was dragging him to the surface by the mouth. I made sure I didn't move that arm the whole way up so I wouldn't dislodge his regulator. The third diver saw my weightbelt come off and retrieved it before surfacing. My ascent buddy had no clue what had happened he just knew he was diving along then he was being dragged to the surface by his teeth. He must not have been too annoyed, he married me a few years later

First: Make sure your weights are properly secured, the webbing should be running straight through the buckle or it will force the buckle open. Replace any faulty buckles or worn webbing.
Second: Tighten your weightbelt after you descend and your wetsuit compresses
Third: Check the weightbelt regularly throughout your dive to make sure it's where it is supposed to be. It just takes a moment to reach down and touch it.
Ber :lilbunny:

 

[Jim Lapenta]

. My ascent buddy had no clue what had happened he just knew he was diving along then he was being dragged to the surface by his teeth. He must not have been too annoyed, he married me a few years later
Ber :lilbunny:

He must have thought it was a come on.:sappy: Kinda like a caveman whacking a girl over the head and dragging her out of the cave:11: . Very smoooth Ber .

 

[Ber Rabbit]

He must have thought it was a come on.:sappy: Kinda like a caveman whacking a girl over the head and dragging her out of the cave:11: . Very smoooth Ber .

LOL! Does that make me a Dom? It's funny to hear him tell the story :blinking:
Ber :lilbunny:

 

[DBailey]

If you lose your weight belt/pockets, it is NEVER acceptable to grab onto another diver. You are putting them at risk. Why try to potentially injure two people? If the other diver wants to help you by grabbing you, then that is their choice and they are assuming the risk.

If you lose your weight belt/pockets here are what you can try to do...

- Grab onto something stationary.
- Go feet up so you can hopefully kick downward some to slow the ascent.
- Flare out (think starfish form) to create as much drag as possible to slow the ascent.

 

[Jim Lapenta]

Along with dumping the air out of the bc and BREATHE!!

 

[Bobby_M]

Personally, I feel that if you can't stay down by finning, you have WAY too much ditchable weight to begin with. Whenever I see people with 20+ pounds on a belt, I think it's a disaster waiting to happen. At least if you have two 10 pound integrated pockets, the worst that can happen is one gets deployed by accident. If you still choose to use a belt, put at least half in your BC pockets or use trim weights on your harness or tank.

On the last bunch of warm water dives in my 3/2mil, I used 4 pounds in my non-ditchable trim pockets and 5 pounds in each of my integrated pockets. Losing one of the ditchable sides would give me a little trouble, but I could easily fin down if I had to. If I were near the bottom, I'd grab a rock or a handful of sand to fill my BC pocket.

I recently dove with a guy that had 30 pounds on his belt and wore a 7mm farmer john. I warned him that if he lost his weight at depth and tried taking me for a ride, I would gouge his eyes out on the way up ;-)

Bobby

 

[Airborne!]

Hmmm…someone being way over weighted and then grabbing me unexpectedly when they lose their belt so we can both shoot to the surface? Note to self…always always always carry a knife. :cut:
Seriously, I take great pride in properly weighting myself for dives. It is a wonder so many people still cannot grasp the basics of buoyancy, but I guess you do what you were taught.

 

[JohnW]

Whenever I see people with 20+ pounds on a belt, I think it's a disaster waiting to happen.
Bobby

Good point, it's just too easy to split the weight up. I've actually seen people diving with there weight belt were it's fallen down around there knees, and there constantly pulling it up.

I usually need 30 lbs in my Drysuit with my heavy polar undies. I switched to a steel tank (+ 4lbs) I stick 20 lbs(10lbs a side in my front BC Pockets and 6lbs(3 per side) in the Back trim Pockets. Nice and cheap to do, plus I have an extra 500 lbs of Air in the HP Steel. If I ever needed the front 20lbs are on a ripcord system.